Physically, it's not difficult to spot the family resemblance to its predecessor. The One M8 has a 5-inch display, making it marginally bigger than the 4.7-inches of the old HD One. Both displays have full HD resolutions.
Andrew Hoyle/CNET

HTC unveiled the HTC One M8 at a press conference Tuesday, showing off a slightly larger screen for its signature aluminum body, while announcing a massive rollout of the phone.

Check out CNET's full review of HTC's latest device. The new flagship phone goes on sale almost immediately following the press conference. That means customers can purchase the phone starting at 1 p.m. ET on Tuesday, at several US carriers, including AT&T, Sprint, Verizon, Rogers, Bell, Telus. The device will also be available in Verizon stores after 1 p.m. ET. Other carriers, including those in countries outside the US, will see the device within the first few weeks of April. Read more details on its availability here.

At its event, HTC President Peter Chou made sure to talk at length about the HTC One M8's metal body, which is now more curved.

"To make HTC M8 even more premium feeling, we have developed another brand new process to create this stunning finish with this rough hairline texture," he said, promoting the finish while also taking a jab at competitor Samsung, which has been criticized for having plastic phones.

In addition to a focus on design, HTC rolled out its new versions of its user interface, called Sense 6, and its news feed, Blinkfeed. HTC is also rolling out Sense 6 to the original HTC One devices this spring.

The company said its opening up the new Blinkfeed to developers, so users can track other content besides articles and news. The first of HTC's partners are FourSquare, which will publish restaurant recommendations in the feed, and Fitbit which can turn the feed into a fitness activity tracker.

HTC also highlighted its new Signature Boom speakers and promised 40 percent more battery life than the old HTC One. It can last up to two weeks in standby mode, according to Jonah Becker, HTC's associate vice president of design. The phone also incorporates gesture controls, like answering a call by just holding it up to your ear, or checking the time by double tapping the screen.

Becker also promised that the new HTC One M8's camera will take better photos in all lighting and shoot 50 percent faster than before. For more on the camera, read CNET Editor Andrew Hoyle took a deep dive into the camera's features.

Prior to this announcement, there were plenty of leaks and rumors, including a report that said Verizon secured an exclusive deal to start selling the HTC One M8 in the US on Wednesday, just a day after Tuesday's event. Global sales were expected to commence two weeks after, according to the report.

HTC's original HTC One drew rave reviews, including one from CNET Editor Brian Bennett, who called it "a beautifully crafted, near-ideal smartphone." Known for its sleek aluminum casing and high-performing camera, the HTC was screen as a possible competitor to Samsung's flagship smartphones.

But, the company's profits and sales continued to fall, and its devices have yet to achieve the popularity held by Samsung's popular Galaxy line of devices.

This latest HTC phone features a slightly bigger screen and higher megapixal cameras, as well as a new expandable storage slot. Check out a full rundown on the two phones in this side-by-side comparison. As CNET editor Jessica Dolcort points out while pitting the HTC phone against its Apple and Samsung rivals, the new slot addresses a shortcoming the original device had when going up against Samsung's phones. She explains in detail why Samsung should be worried about the new device.